When pulp or paper in the form of bales is to be dissolved for the final production of paper, the wires that keep the bales together must be removed. This may be done manually or mechanically. It is especially important to make sure that no wire remains with the pulp since this could cause great damage to the equipment in the following process steps.
The mechanical removal is usually carried out as a two-step operation. At first, the wires are cut off by means of one or more cutting devices and then the cut wires are removed. The removal is normally carried out by means of winding devices, which grab one end of the wire, or the centre of the wire and then rotate such that the wires are wound onto the device.
One such device is known from the American patent document U.S. Pat. No. 4,850,087. This known device is equipped with gripping members for transferring the wires from the place of cutting to the place of winding. This, however, adds another step, which makes the operation sensitive to possible errors.
In WO 9213768, a device is described in which the cutting and the removal are combined in one single elongated arrangement having an inner element and a surrounding tubular element, both comprising an indented edge, whereby the two elements rotate in relation to each other such that the wire is cut off and caught between the two elements, after which the elements rotate together to wind the cut wire around the arrangement.
A problem with this device is that the arrangement does not always grip the wires correctly, or on the contrary, the wires get caught between the two parts such that the operation has to be interrupted to release the wires. Furthermore, the arrangement needs a fairly complicated driving mechanism in order to accomplish all the steps.
Another problem is that it risks fraying the entire side of the bale since the cutting is carried out over the whole side of the bale instead of being centred at the positions where the wire is actually located. This results in wastage, which is undesired since it requires cleaning of the working area as well as decreases the degree of capacity utilisation of the bale material.
An object of the invention is to provide an improved device for the cutting and removal of wires from bales, which is reliable and easy to implement and which solves the above mentioned problems.
The said objects are obtained by means of the device, as disclosed in the claims, for the cutting and removal of wires from bales, such as pulp bales, paper bales and the like, which device is intended to remove all wires from a bale that is provided with at least two wires. The device comprises two cutting units and two winding units that are positioned pairwise opposite each other, on one side each of a working location W, for the pairwise cutting off and removal of two wires that are arranged in parallel.
Preferably, a turning tool or turning plate is arranged at the centre of a working location W, in which the bale is intended to be positioned when its wires are cut off and removed from it, whereby the cutting unit and the winding unit are positioned opposite each other, on one side each of the working location (W), and whereby the turning tool or turning plate is arranged to be able to turn the bale 90° to relocate it into a position in which wires placed crosswise with respect to the first wires may be cut off and unwound.
Preferably, there are also driving units arranged to move the cutting unit and the winding unit towards and from the centre of the working location, between a working position, in which they are to be positioned when the wires are to be cut off and unwound, and a resting position, in which they are to be positioned out of reach of the bale when it is turned.
Moreover, conveyor belts may be arranged to transport the bale into and out of the working location (W), respectively.
As a result of the above disclosed device and cutting unit, an efficient and reliable cutting of bale wires is achieved, which reduces the wastage of pulp in connection with cutting of the wires.
An additional advantage of the invention is that the driving of the different tools for winding and for cutting may be the same. The only thing that has to differ between the two devices is the head of the tool, where the cutting tool shall be provided with two opposite surfaces, of which at least one is sharp, while the winding tool is instead provided with a gripping appliance for picking up the wires.